hw/arm_gic: Add qdev property for GIC revision

GIC behaviour can be different between revision 1 and
2 of the architectural GIC specification; we also have
to handle the legacy 11MPCore GIC, which is different
again in some places. Introduce a qdev property so we
can behave appropriately.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/a15mpcore.c

@@ -44,6 +44,7 @@ static int a15mp_priv_init(SysBusDevice *dev)
     s->gic = qdev_create(NULL, "arm_gic");
     qdev_prop_set_uint32(s->gic, "num-cpu", s->num_cpu);
     qdev_prop_set_uint32(s->gic, "num-irq", s->num_irq);
+    qdev_prop_set_uint32(s->gic, "revision", 2);
     qdev_init_nofail(s->gic);
     busdev = sysbus_from_qdev(s->gic);
 

hw/arm11mpcore.c

@@ -123,6 +123,8 @@ static int mpcore_priv_init(SysBusDevice *dev)
     s->gic = qdev_create(NULL, "arm_gic");
     qdev_prop_set_uint32(s->gic, "num-cpu", s->num_cpu);
     qdev_prop_set_uint32(s->gic, "num-irq", s->num_irq);
+    /* Request the legacy 11MPCore GIC behaviour: */
+    qdev_prop_set_uint32(s->gic, "revision", 0);
     qdev_init_nofail(s->gic);
 
     /* Pass through outbound IRQ lines from the GIC */

hw/arm_gic.c

@@ -119,8 +119,13 @@ typedef struct gic_state
     struct gic_state *backref[NCPU];
     MemoryRegion cpuiomem[NCPU+1]; /* CPU interfaces */
     uint32_t num_irq;
+    uint32_t revision;
 } gic_state;
 
+/* The special cases for the revision property: */
+#define REV_11MPCORE 0
+#define REV_NVIC 0xffffffff
+
 static inline int gic_get_current_cpu(gic_state *s)
 {
     if (s->num_cpu > 1) {
@@ -880,6 +885,11 @@ static int arm_gic_init(SysBusDevice *dev)
 static Property arm_gic_properties[] = {
     DEFINE_PROP_UINT32("num-cpu", gic_state, num_cpu, 1),
     DEFINE_PROP_UINT32("num-irq", gic_state, num_irq, 32),
+    /* Revision can be 1 or 2 for GIC architecture specification
+     * versions 1 or 2, or 0 to indicate the legacy 11MPCore GIC.
+     * (Internally, 0xffffffff also indicates "not a GIC but an NVIC".)
+     */
+    DEFINE_PROP_UINT32("revision", gic_state, revision, 1),
     DEFINE_PROP_END_OF_LIST(),
 };
 

hw/armv7m_nvic.c

@@ -447,6 +447,8 @@ static int armv7m_nvic_init(SysBusDevice *dev)
 
     /* The NVIC always has only one CPU */
     s->gic.num_cpu = 1;
+    /* Tell the common code we're an NVIC */
+    s->gic.revision = 0xffffffff;
     gic_init(&s->gic, s->num_irq);
     /* The NVIC and system controller register area looks like this:
      *  0..0xff : system control registers, including systick